The long-range goal of these studies is to determine the mechanisms by which ion transport occurs across blood-aqueous and blood-vitreous barriers into and out of the ocular lens, and how aberrations of these processes contribute to glaucoma or cataract. The specific areas of proposed research related to cataract include studies of possible deleterious effects of elevated levels of lens calcium on hydration, content and fluxes of electrolytes, and bioelectric potential, an unusually sensitive and rapid means of assessing lens viability. The mechanism by which the very low levels of calcium are maintained normally in the lens will be studied by determining the mode of transport of calcium into and out of the lens. Investigations are planned to establish values of electrolyte composition and bioelectric potentials in normal and human lenses and determine rates at which ions normally are actively and passively transported into and out of them. It is also proposed to study the effects of various conditions associated with storage on lenses obtained postmortem using alterations in lens chemistry and bioelectric potential as a means of determining the physiologic state of the lens. Two different kinds of investigations are proposed that relate to intraocular pressure hence of potential relevance to the glaucoma problem, and the first may also have some bearing on cataract. Investigations that relate to intraocular fluids and pressure include an extensive analysis of human aqueous humor where emphasis will be placed on changes in composition that may occur with age which has as one of its goals to learn whether any changes may provide a clue indicative of altered nutrition in the lens that could be a contributing cause of cataract. A second study in this area of research will deal with transport properties of the pigment epithelium and how it regulates movement of substances between blood and vitreous thereby affecting intracoular pressure. Fluxes of ion and associated electrical activity.